(VAR x y ) (RULES f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) ) (COMMENT TRS variant of the rpo-terminating SRS abc -> bacb )